New composition operator: repeat

We propose adding a new composition operator to execute its content multiple times.

scenario my_scenario:
    v: vehicle
    do repeat(count: 10):
        serial:
            v.change_speed(target: 50kph, rate_peak: 4mpss)
            v.change_speed(target: 10kph, rate_peak: 10mpss)

It may contain only one direct child. If count is omitted, the number of repeats would be infinite. Question: Should the constranits on the contained do-members be resolved once, before the first iteration starts, so all iterations run with the same parameter values, or should the constraints be resolved separately for each iteration to allow for parameter variation across iterations?